The conventional bed which has a flat upper surface in general is usually made of a wooden or steel structure. Since these conventional beds are generally too hard and uncomfortable to the sleepers, the redesigned bed which uses spring structures provides a more comfortable and softer sleeping area than the conventional beds.
The first type of spring bed structure generally comprises a plurality of vertically compressible springs which are clamped between an upper mattress pad and a lower mattress pad. The spring bed structure is covered by a cloth casing all over its outer surface. The second type of spring bed structure has a pad casing on its upper surface and a cloth casing on its lower surface. It is difficult to clean the mattress casings of the second type of spring bed structure thoroughly. The methods of cleaning the mattress casings are limited to bask the bed mattress under the sunshine and to vaccum the bed mattress only, as rinsing and washing may damage the bed mattress. Furthermore, it is so inconvenient that the user has to remove the bed mattress outdoors in order to bask it. The pad casing or the cloth casing of the mattress cannot be repaired nor replaced owing to the torn or soiled damage, so the whole spring bed mattress has to be replaced leaving the bed frame without the mattress. The fixed elasticity of the spring bed structures is another disadvantage for the users. The user cannot adjust the elasticity of a spring bed structure to an exact hardness to suit his feeling. That is the reason why a user cannot sleep comfortably in a spring bed structure other than his own. The huge volumes of the spring bed structures that are produced currently may cause two problems. The first problem which is described as above cannot be overcomed by the users in general. The second problem is that the manufacturer or the store owner has to store the spring bed structures in a large storage area and must hire more workers to move the heavy spring bed structures.